import java.util.Scanner;

class qiuzuheshu{
        public static int diedai (int n,int m){
                if(m==1)
                        return n;
                else if(m==0||m==n)
                        return 1;
                else if(n<m||n==0)
                        return 0;
                else
                        return diedai(n-1,m-1)+diedai(n-1,m);
}
}
public class zuheshusuanfa{
        public static void main(String[] args){
                System.out.println("C(n,m)请输入n，m：");
                Scanner shuzi=new Scanner(System.in);
                qiuzuheshu sum=new qiuzuheshu();
                int a=shuzi.nextInt();
                int b=shuzi.nextInt();
                if(a<b||a==0)
                        System.out.println("输入错误，需要n>m且n>0");
                else
                System.out.println("组合数结果为"+sum.diedai(a,b));


        }

}


